Traditionally baseball managers have tried to put a player with a high On-Base Percentage (OBP) with the ability to steal in the lead-off spot. The second batter’s role would be to do whatever it takes to move the lead-off runner to second base so that he would be in scoring position. This means the second batter would bunt or try to hit into a hit-and-run situation and give up his opportunity to get on base. This is exactly the strategy the Angels used in 2013, Mike Trout batted first and Erick Aybar batted second. So why the change in 2014? What would the Angels want Mike Trout to sacrifice his at-bats in order to advance the much slower base runner Kole Calhoun?
The simple answer is: math. The much longer answer is also: math. Baseball has a long season which produces some pretty in-depth statistics. Analyst can take those stats and put them into statistical models to help them figure out which sorts of strategies work best. There’s no need to play an entire season with Mike Trout in the lead-off spot and then another season with him in the 2nd spot in the order to see which is the better option. You can just run the stats through a hypothetical season as many times as you want and see which produces the best numbers. Because baseball has been played for over a hundred years you can compare these hypothetical seasons to actual seasons to see if they are producing realistic numbers.
What’s been discovered is that traditional baseball strategy has been wrong. First off, batting order isn’t all that important. It may seem like it in any given situation but managers can’t adjust their lineups very much in real-game situations. They have to go with a more generalized approach for the entire season. It’s still true that you want your best batters at the top of the order because they will come to bat more often. Statistical models have shown that you actually want your best batters batting #2 and #4. This gives them the most opportunities to be batting with runners in scoring position. Second, when it does matter, it’s most important to avoid outs in the #1, #4 and #2 positions. One of the worst things a manager can do is have their second batter intentionally get an out in order to move a runner.
When Mike Trout bats second it gives him the opportunity to see what the opposing pitchers pitches look like. He gets to see what it’s like for Calhoun to face the same pitcher. If Calhoun gets on base Trout IS the best batter on the team, so the chances are the best for team to have the lead runner advance when Trout gets on base. Because the #1 batter should be much better than the #8 and #9 batter the chances are higher that the #2 batter sees runners on base than the #1 batter. If Calhoun (or the #8 or #9 batter) doesn’t get on base, Trout is still a speed option for the team. There will still be plenty of opportunities for him to steal bases because the other batters aren’t likely to be on the base path in front of him more than 40% of the time.